The army Saturday reinforced security in the jungle along the Colombian border following an attack by suspected guerrillas that killed three Brazilian soldiers and wounded nine others, officials said.

Meanwhile, the governments of Brazil and Colombia said they would collaborate to prevent similar incidents in the Amazon.The Brazilian army flew 240 soldiers to patrol the border after 40 suspected Colombian guerrillas attacked 17 Brazilian soldiers who were scouting for illegal mineral prospectors in the Amazon jungle.

The surprise attack occurred Tuesday but was not discovered until Friday by replacement soldiers who arrived by river after a three-day trip.

Officials said the gunmen took the solders' weapons and radios, making it impossible for the survivors to report the attack.

Brazil's foreign relations minister Francisco Rezek said the shootings in northwestern Brazil were the first the army had suffered from foreign guerrillas.

He said Brazil offered to work with Colombia to prevent future acts by the Revolutionary Armed Forces of Colombia, the group suspected of the shootings.

"We made it clear to the Colombian government that the Brazilian government is available to collaborate to clean up the border, maintain the border security and to guarantee that future episodes of this nature will not happen again," Rezek said Saturday.